package com.demo.mq.send;

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendCallback;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.common.CountDownLatch2;
import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.remoting.common.RemotingHelper;

import java.util.concurrent.TimeUnit;

/**
 * 发送异步消息
 * 异步消息通常用在对响应时间敏感的业务场景，即发送端不能容忍长时间地等待Broker的响应。
 * @author mifei
 * @create 2021-01-08 16:09
 **/
public class AsyncProducer {
	public static void main(String[] args) throws Exception {
		// 实例化消息生产者Producer
		DefaultMQProducer producer = new DefaultMQProducer("producer_group");
		// 设置NameServer的地址
		producer.setNamesrvAddr("localhost:9876");
		// 启动Producer实例
		producer.start();
		producer.setRetryTimesWhenSendAsyncFailed(0);

		int messageCount = 100;
		// 根据消息数量实例化倒计时计算器
		final CountDownLatch2 countDownLatch = new CountDownLatch2(messageCount);
		for (int i = 0; i < messageCount; i++) {
			final int index = i;
			// 创建消息，并指定Topic，Tag和消息体
			Message msg = new Message("TopicTest",
					"TagA",
					"OrderID188",
					"Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));
			// SendCallback接收异步返回结果的回调
			producer.send(msg, new SendCallback() {
				@Override
				public void onSuccess(SendResult sendResult) {
					System.out.printf("%-10d OK %s %n", index,
							sendResult.getMsgId());
				}
				@Override
				public void onException(Throwable e) {
					System.out.printf("%-10d Exception %s %n", index, e);
					e.printStackTrace();
				}
			});
		}
		// 等待5s
		countDownLatch.await(5, TimeUnit.SECONDS);
		// 如果不再发送消息，关闭Producer实例。
		producer.shutdown();
	}
}
